FPDebug: refactored reading image-file, ported elf reader from duby

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42925 4005530d-fff6-0310-9dd1-cebe43e6787f
FPDebug: auto include win and elf reader 

git-svn-id: http://svn.freepascal.org/svn/lazarus/trunk@42926 4005530d-fff6-0310-9dd1-cebe43e6787f